[FIX] website: apply custom font size on buttons inside the header

Steps to reproduce:
- Enter in edit mode.
- Select the 'Header' menu.
- Switch the default template to 'Rounded box menu'.
- Select again the 'Header' menu and on the 'Navbar' details, update the
format value (i.e: 10px) and save.

-> Problem: some buttons are not affected by the change of the format
value.

The problem is that since [1], those buttons have the `rounded-circle`
class so their font size is not the custom one (but it is the value of
`$font-size-base` instead). To solve the problem, the css rule has been
adapted in order to force the font size of the buttons inside the header
to the custom value if it exists.

[1]: odoo@e3e9c49

opw-3810794

closes odoo#158467

X-original-commit: 75d1245
Signed-off-by: Romain Derie (rde) <[email protected]>
Signed-off-by: Colin Louis (loco) <[email protected]>

Author: loco-odoo

addons/website/static/src/scss/website.scss

@@ -374,7 +374,7 @@ $-header-nav-link-height: $nav-link-height;
         font-size: o-website-value('header-font-size');
 
         .dropdown-menu, .btn {
-            font-size: inherit;
+            font-size: inherit !important;
         }
     }
 }